There are many instances when it is necessary to empty a number of bottles sealed with a crown cap. For example, it may well be that a large number of bottles containing defective liquid are returned to the manufacturer and the bottles are required for reuse. An alternative situation which more often arises, is in the use of automatic bottling lines. If an operation on such a line is defective, for example, the volume of liquid introduced into each bottle is incorrect, due to the high speed operation of such lines the number of bottles filled and sealed before the situation is detected may run into hundreds, all of which upon detection will have to be emptied and returned for refilling. Moreover, the same problem arises if, for example, the bottle label is incorrectly or so badly applied, subsequent to being filled, that the product is considered commercially unpresentable. Originally, such bottles had to be decapped and emptied by hand which was obviously a tedious and time consuming operation.
Attempts have been made therefore to provide means for decapping and emptying such bottles automatically. For example, British patent specification No. 1,316,252 teaches an apparatus for opening and emptying filled bottles sealed with a crown cap. The apparatus is complex and includes a decapping station wherein the bottle is supported in a horizontal position and plunger means are arranged to strike the cap thrusting the bottle rearwards whilst the cap is retained at that station: the bottle then falls under gravity in an inverted position whereupon the liquid inside the bottle is discharged. As mentioned previously the apparatus required is relatively complex requiring means to locate the bottle in the horizontal position and subsequently receive the bottle in its decapped state. More importantly, the shock on the bottle due to the action of the plunger is obviously quite severe. An alternative apparatus presently available comprises a horizontal conveyor for delivering the capped, filled, bottles to a decapping station. At the decapping station, there is provided a wheel rotating in a vertical plane containing the conveyor, said wheel being provided with two types of tools: a metal peg arranged to crease and deform the cap and a hook arranged to follow the peg, grip the underlying edge of the crown cap and rip or yank the cap off the bottle due to the opposite relative motion of the hook and the bottle. Obviously, the bottle must be restrained whilst the cap, which is still affixed to the bottle neck, is being ripped off and this is effected by way of star wheels located to a side of the decapping zone. The decapped bottle is then emptied in some manner. Again, a disadvantage of this apparatus is the violent way in which the crown cap is removed and this results in many cases in the sealing ring on the bottle mouth being chipped. Major problems arise when the chipping is not excessive since in such cases it is generally not detected and the bottle may be recycled resulting in damage to the automatic filling equipment, such as sealing washers etc. being ripped or torn by the chipped bottle neck. This further augments the original problem since damage to the seal on the bottling equipment causes further inaccuracy in bottle filling and produces more defectively filled bottles. An additional disadvantage of this equipment is that the crown caps are not removed in a consistent or controlled manner and their orderly collection is therefore difficult, if not impossible. Indeed, it has been found that many freed caps merely fall onto the conveyor belt and associated equipment causing foul-ups.
It is an object of the present invention to provide a decapping apparatus which may rapidly, and in a non-violent, controlled manner remove crown caps from filled bottles.